Smack dab in the center of town, the Boston Common encompasses a whopping 50 acres. It's a popular gathering spot for dog walkers, joggers, cart vendors, studying students and families and yes, a fair amount of homeless people. Whereas the Public Garden is quiet and contained, the adjacent Commons is open and bustling. The park has belonged to the people of Boston since the 1630s, when Reverend Blackstone sold the tract to the Puritans. Designated by these early Bostonians as "Common Field" forever reserved for public use, this landmark has served over the centuries as pastureland, military training ground, public execution site and concert venue.